Improvement in folding spiral stairs



B. P. CARD. Folding Spiral- Stairs.

9 7 8 8 H p A d t n .w. 3 m 8 sag WM UNITED STATES PATENT OFFICE.

BENJAMIN F. CARD, OF BROOKLYN, NEW YORK.

IMPROVEMENT IN FOLDING SPIRAL STAIRS.

Specification forming part of Letters Patent No. 214,022, dated April 8,1879 application filed September 11, 1878.

To all whom it may concern:

Be it known that I, BENJAMIN F. CARD, of the city of Brooklyn, county ofKings, State of New York, have invented a new and useful Improvement inFolding Spiral Stairs for Fire- Escapes, &c., of which the following isa specification:

The object of my invention is to make spiral stairs to be used forfire-escapes, &c., so that the steps shall be movable on a verticalshaft, and be readily folded up and opened when desired either by handor other power.

The invention consists in an arrangement of steps on a vertical shaft,so as to give them a circular movement, and also in applyingintermediate mechanisms connecting the steps with each other, andlikewise suitable mechanisms to rotate the vertical shaft and stepsconnected therewith.

In the accompanying drawings, in which similar letters of referenceindicate like parts,

Figure 1 represents a plan or top view of the stairs when the steps areunfolded. Fig. 2 is a front view thereof. Fig. 3 is a cross-section of aportion of the stairs, showing the connections between the steps. Fig. 4is a top view of the steps when folded up below the bracket-arm. Fig. 5is a front view of the steps when folded up. Fig. 6 shows a portion ofthe stairs and railing. Fig. 7 is a front view of the lock. Fig. 8 is across-section thereof, showing one of the steps held by the look.

In the construction of my improved folding spiral stairs, the steps Aare made in triangular shape, or with their sides parallel, having acircular hole in one end. The steps A are placed' on the vertical shaftB, one above the other, and contain a hub, whereby sufficient bearingis'secured, so that they are held in the plane of their rotation. (SeeFig. 2.) The vertical shaft B is suitably journaled at each end in boxesor bearings, and the lower step A is secured to the shaft B by a pin orbolt, while the uppermost step is secured to the building or frame-workthat holds the upper end of they shaft B, and is held in position on theshaft B by the nut 0. (See Fig. 2.) Each alternate step A has a slot,66, running across its outer end on the face of the step, (see Fig. 1,)while the other steps A have on their extreme outer end two pins orbolts, b, one projecting up sufficiently high to make a connection withthe step above it, (see Fig. 3,) and the other pin or bolt b projectingdown sufficient distance to make a connection with steps A below it. Ata suitable distance from the uppermost step A, and on one of the stepsthat are parallel in a perpendicular distance to the uppermost step A,is placed on the outer end of the step a V-shaped dovetailed catch orlock, 0, or its equivalent. Attached to the wall of the building, towhich a bracket for the vertical shaft B is connected, is acorresponding V-shaped and dovetailed recess, F, for receiving the V-shaped lock or catch e. (See Figs. 7 and 8.)

Placed at the outer ends, and in a suitable position with the surface ofthe steps A, and secured to the steps A, are placed rods 9, formingstandards for a railing. ()n the upper ends of these rods 9, and to eachone, is secured a chain or rope, h, thus forming a railing when thestairs are open. (See Fig. 6.)

The operation of my device is as follows: The folding spiral stairs arefirst secured to a building or frame-work by attaching the uppermoststep A to such frame-work in any suitable manner, so as to be secure.The lower end of the vertical shaft B is likewise secured to a properfoundation. When it is desired to operate the device, power is appliedto the crank or disk F, which transmits motion to the vertical shaft Bby means of the gearwheel E, in connection with the gear-wheel D,secured to the vertical shaft B. This causes the vertical shaft B torevolve, carrying with it the lower step A, which, in turn, operates thestep above it by means of the pins b, and so on until all the steps areunfolded and in position, forming a complete spiral stairway. The chainor-rope h, which is secured to the rods or standards 9, forms a railingto the stairs. The unfolding of the steps gives tension to the rope orchain, so as to make it perfectly firm.

In order to hold the stairs firmly in position and avoid all swaying orunsteadiness, I have a.V-shaped dovetailed lock or catch, 0, secured tothe outer end of the steps at proper intervals, with a correspondingV-shaped dovetailed recess, f, attached to the building, into which theV-shaped lock or catch enters, which looks and holds the steps. Thislock or catch is placed at a window or door at each story. (See Fig. 2.)

By applying power to the crank f, the steps are folded up in a compactspace and locked by the bolt (1, thus preventing any egress or ingressby means of the steps from the windows or doors.

Having thus described my invention, what I claim, and desire to secureby Letters l'at cut, is-

1. Acontinuouslyopeningand folding spiral stair for the inside andoutside of buildings, the steps of which are secured at one end to avertical operating-shaft, whereby the steps are opened or spread out toform the stairs, or folded up, substantially as described.

2. In a folding spiral staircase, the combination of revolving verticalshaft 13 with movable steps A, constructed and arranged substantially asdescribed, and for the purpose set forth.

3. In a folding spiral staircase, the eombi nation of the revolvingvertical shaft 1 with movable steps A, slots (1, and pins b, constructedand arranged substantially as described, and for the purpose set forth.

4. In a folding spiral staircase, the combination of the revolvingvertical shaft B with movable steps A, slots a, pins b, lock 0, andrecessf, constructed and arranged substantially as described, and forthe purpose set forth.

5. In a folding spiral staircase, the combination of the revolvingvertical shaft B, mov able steps A, slots (1, pins b, lock e, recess f,standards and railings h, constructed and arran gcd substantially asdescribed, and for the purpose set forth.

6. In a folding spiral staircase, the combination of the revolvingvertical shaft B, movable steps A, slots 01, pins b, lock 6, recess f,standards g, railing h, disk F, gear-wheels l) and E, and pin 1],constructed and arranged substantially as described, and for the purposeset forth.

In testimony that I claim the foregoing I have hereunto set my hand this7th day ot September, 1878.

BENJAMIN F. CARI).

In presence of- EDGAR J. PHILLIPS, WILLIAM 1. Bean.

